This invention relates to apparatus for translating rotary motion into substantially linear motion, and more particularly to a motion translating mechanism of the type defined which is well suited for use as a window regulator of passenger cars, among other applications. In this particular application the apparatus of this invention serves to convert the bidirectional rotation of a hand crank or of a reversible electric motor into the up and down motion of a pane or panel of glass or like material relative to a door frame of the vehicle.
Among the wide variety of devices heretofore suggested and used for opening and closing vehicular windows is the one employing a steel wire rope or cable as the primary means of motion translation. A typical conventional construction of this type of window regulator is such that the cable is looped about a pair of guide reels or nonrotatable cable guides disposed at the opposite ends of a guide rail which is to be mounted in an upstanding attitude to the vehicular door frame for guiding the up and down motion of a carriage supporting the windowpane. One of the two stretches of the cable, extending between the pair of guide reels, is coupled to the windowpane carriage. Extending away from the guide rail in order to avoid interference with the windowpane carriage, the other cable stretch is wound several turns about a drive reel positioned some distance away from the guide rail. A hand crank or a reversible electric motor is the familiar means for bidirectionally revolving the drive reel.
Thus, with the bidirectional rotation of the drive pulley, the windowpane carriage slides up and down over the upstanding guide rail thereby moving the windowpane between the closed and open positions with respect to the door frame.
This known cable type apparatus posseses the advantages of simple construction, reliable operation and low manufacturing cost. Offsetting all these advantages is its large space requirement arising from the positioning of the drive reel a substantial distance away from the guide rail. It is, indeed, this weakness of the conventional motion translating mechanism that has restricted its application to vehicular window regulators in the face of its noted strengths. The mechanism will certainly lend itself to a diversity of different applications only if it is of more compact construction.
The automotive industry itself has long awaited the advent of more compact window regulators. The doors of passenger cars today contain a variety of devices in addition to window regulators, examples being door locks and their remote controls, cigarette lighters and ashtrays, windshield wiper controls, seat adjustment controls, and rearview mirrors and controls. Thus, with the introduction of many sophisticated door attachments and accessories, vehicle doors are becoming more and more crowded than they used to be, imposing proportionately greater limitations on the spaces available for window regulators.